After the success of the Apollo 8 mission in orbiting the moon, Apollo 9’s mission was quite ambitious. Perhaps, it did not have the glamor of circling another world, but it was an important next step to getting to the moon.

Apollo 9 was an Earth-orbiting mission that tested out the Apollo lunar module for the first time. The lunar module was designed to bring astronauts to the surface of the moon and NASA wanted to ensure that the spacecraft worked well in Earth orbit before testing it at the moon.
Future crews had to be comfortable with docking and undocking the two Apollo spacecraft — necessary maneuvers for the lunar module to land on the moon, and for the command module to bring the astronauts from lunar orbit back to Earth.

The command module was called Gumdrop, and the lunar module: Spider. They were named so because of their resemblance. The Apollo 9 mission was the first manned flight of all Apollo lunar hardware in Earth orbit and the first manned flight of the lunar module. The crew included Commander Jim McDivitt, Dave Scott, and Russell Schweickart. The Apollo 9 mission was launched from Cape Kennedy at 11 a.m. EST on March 3, 1969, from Launch complex 39A. This launch was the first Saturn V/Apollo Spacecraft in full lunar mission configuration and carried the largest payload ever placed in orbit.
The primary objectives were as follows:
- Demonstrate crew, space vehicle and mission support facilities performance during a manned Saturn V mission with the command-service module (CSM) and the lunar module (LM)
- Demonstrate LM/crew performance
- Demonstrate docking, inter-vehicular crew transfer, extravehicular capability and LM-active rendezvous and docking, and
- Conduct CSM/LM consumables assessment.

All primary objectives were accomplished. Lunar module pilot Russel L. Schweickart performed a 37-minute EVA. Human reactions to space and weightlessness were tested in 152 orbits. And while the module performed well, the astronauts were forced to modify a spacewalk after one of them fell ill during the flight.
The crew had remarkable success in sighting objects using the crewman optical alignment sight (COAS). Their success confirmed the thesis that the visual acuity of the human eye is increased in space. One example is their sighting of the Pegasus II Satellite at a range of approximately 1,000 miles.
Gumdrop is on display at the San Diego Air and Space Museum, while Spider burned up as planned in the Earth’s atmosphere.

Apollo 9 was an important engineering test for the lunar module. Even though the crew did not gain the prestige of heading out to the moon, and even though the mission is not well-remembered by the public today, Apollo 9 was a crucial step in getting ready for lunar landings.
References:
https://www.nasa.gov/mission_pages/apollo/missions/apollo9.html
https://www.space.com/17616-apollo-9.html
https://airandspace.si.edu/explore-and-learn/topics/apollo/apollo-program/orbital-missions/apollo9.cfm
https://en.wikipedia.org/wiki/File:Apollo_9_Command_Module.jpg
In the next article, we will cover the details about Apollo 10 Mission.